Chinese Pigs
Help U.S. Researchers

To try to increase the number of
offspring U.S. pigs produce, Agricultural
Research Service scientists have been studying Chinese pigs since the late
1980s.

In the process, researchers at the Roman L. Hruska U.S. Meat Animal Research
Center (MARC) have found many
interesting reproductive facts about the Meishan (pronounced MAY-shawn) pigs of
southern China. The first was that the Meishan males had five to seven times
more follicle stimulating hormone (FSH) in their blood than U.S. boars. FSH
aids in the production of sperm.

Meishan males' testes were 40 percent smaller than those of U.S. boars. ARS
researchers found that a gene or genes on the X-chromosome affects the size of
the Meishan male's testes, whereas in rodents, for example, testes size is more
affected by genes on the Y-chromosome.

Scientists also like the fact that the Meishans provide a good model for
investigating sperm production. According to ARS animal physiologist Joe Ford,
75 percent of newborn pigs in the United States are produced through artificial
insemination, so improving sperm production helps improve pork production
efficiency.

Pork products from Meishans taste as good as pork from conventional breeds.
But for now, Ford's laboratory is only using them as an experimental model to
compare to other breeds of pigs. The meat production is not as desirable
compared to other pigs, because Meishan pork contains more fat, according to
Ford.

Other researchers at MARC are still investigating the female Meishans and
their large litter size. They've found that the females begin puberty in only
60 days, compared to 150 days in other pigs. The females ovulate more eggs per
cycle than American pigs. They also have a greater uterine capacity, meaning
they can deliver more live piglets.

More details about this research are in the
November 2002 issue
of Agricultural Research magazine.